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2017 metris-auxiliary battery malfunction light

29K views 54 replies 13 participants last post by  ColoradoDave 
#1 ·
Hello, my 2017 metris passenger van, 50k miles, zero problems with it-ok, I take that back, the rear washer fluid pump fitting broke, the dealer wanted $600 to repair and replace-I fixed myself with bonding the fitting that cracked haha. Anyway, got a light on instrument panel that comes and goes "AUXILIARY BATTERY MALFUNCTION"...not always on, but maybe half the time I drive. Any remedies for it? and please don't post "take it to a dealer", I am out of warranty and refuse to pay their prices for repair-I will assume its a aux battery is dead maybe? or some fuses?
 
#5 ·
My 2020 135 with start/stop has an extra battery under the passenger seat. I don't know if that's what' meant with the aux battery?
I have a flap facing outwards in my cargo seat bases. I think in the passenger version it is flap to access from the rear.
Anyhow, in my metris the extra one under the seat is is pretty sizable.
There is room and a wire in my driver seat base for a third battery.

On my ML350, when it was maybe 7 years old (?), I got a battery fail / replace notification. The vehicle had under the passenger seat, the oversized main battery and a tiny 12v aux one - like kbcool showed - hidden behind it. One could not see it and certainly not access it unless the big one was pulled out. ( or maybe dealers can if they take the whole seat out )

I recall something about the sedans having these typically near a fuse panel in either the trunk or below the passenger glove box area ... but it can also be in the driver side outside facing dash panel ... that's where the one in my wife's car was hidden (despite the dealer insisting it was in the trunk).
 
#9 ·
Got around to replacing this today. Original battery tested @ 13v today. But, it was warm overnight. So, will see next week if i still get the aux light malfunction as our temps drop into the 30's. Anyways super easy to replace. Popped two 10mm nuts holding the metal cover on. Unplugged the 15 amp automotive type fuse and pulled the spade connectors off the positive and negative terminals. They are impossible to mix up as each spade connector are sized to match the battery terminal. One small, one large. Also the battery just lifts straight up and out of it carrier. Re-assembled w/ no issues so far.
18590
Motor vehicle Mode of transport Gas Automotive exterior Bumper
18591
Audio equipment Bumper Tool Sports equipment Gas
 
#47 ·
Hi all! Greetings from Singapore!

I was wondering if anyone has pictures of how the wiring is like for the relay and on the auxiliary battery terminals? The previous owner of my 2016 Metris (it’s called Vito in my part of the world) removed it for whatever reason and never put it back in. Now I am having trouble getting the auxiliary battery to work again even though the battery was replaced a few days ago.

Would really appreciate any help you guys can give!

Thanks in advance,
Kenn
 
#16 ·
#21 ·
Looks like I'm removing the seat swivel when this job comes up. Rats. Does anyone know if the foam piece the technician removes is the same one that came with the recall? I never installed it because the gap is covered by the RIB Scopema swivel.
 
#19 ·
I would. I bought a duralast 90Ah copy of my under-driver's-seat additional battery. Fits and works like OEM.
 
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#20 · (Edited)
That should be it. Main battery in the front half of passenger seat. Auxiliary battery in the rear half.

This is not the average compact $20 ups / alarm system backup battery, nor the $40 MB equivalent thereof as seen in typical MB sedans and SUVs ... but more like a custom size lawn mower battery with some amps behind it. Still quite expensive for what it is, I agree. Different brand of the same specs should be fine, but may last less long; or may with a little age cause the computer to complain about it sooner. I think in my limited experience, I have seen MB batteries last about 6 - 7 years before needing replacement.

I don't look forward to having to replace mine, with a partition wall and steel plate in the passenger seat base ...

PS: I guess it is more like a motorcycle battery.
Looks like the MB one is $125 online with free shipping ... vs $100 AutoZone

[Edit ... not sure what the motorcycle battery quality and specs are that come in at half that cost]
 
#27 ·
There was a recall for a gap in the passenger seat cover. I have seat swivels so I asked the dealer if they could just give me the part. They were cool about it. The invoice showed the recall performed, but they just left the rectangle of foam and push pins on my passenger seat in the factory part bag, with no reference to my seat swivels on the invoice (which I knew they would not remove or reinstall on the recall given how little time MB would pay the tech for the job).
 
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#23 · (Edited)
Only concern for this battery backup, is I think the mercedes one (Havent pulled mine out yet) is a 12v 12a, but the duralast is 14v 14a? Their (autozone) battery checkers says "it will fit your 2017 metris" but not sure its that reliable.

Icerabbit, the mercedes one you see for $125, can you link, because the mercedes one I found is 170.

This shouldn't be this hard lol.
 
#24 ·
Googled based on the A number:


Next one is AutoHausAZ

Note, they're playing with cross reference numbers, but looks alike and says fits Metris. Not sure why the photo A number would be different.
 
#26 ·
Let us know how it works out!

For a somewhat small difference I'd look at getting the real thing as well, and be guaranteed the MB computer is happy.

When it comes to at home electronic systems, I have gone with some bigger Ah when it fits in the space. Figuring it will last longer or will be less stressed during an outage.
Older vehicles with a big space for the main battery ... as long as it starts & fits, right?
EU vehicles that monitor every little thing, I just shop around. I don't like to skimp around and have to redo it.
I used to swear by Duracell batteries ... but have had those leak new in package before their guaranteed until date.
You never know ... but having less frequent headaches to replace something by buying the right thing has its value.
 
#28 ·
Let us know how it works out!

For a somewhat small difference I'd look at getting the real thing as well, and be guaranteed the MB computer is happy.

When it comes to at home electronic systems, I have gone with some bigger Ah when it fits in the space. Figuring it will last longer or will be less stressed during an outage.
Older vehicles with a big space for the main battery ... as long as it starts & fits, right?
EU vehicles that monitor every little thing, I just shop around. I don't like to skimp around and have to redo it.
I used to swear by Duracell batteries ... but have had those leak new in package before their guaranteed until date.
You never know ... but having less frequent headaches to replace something by buying the right thing has its value.
Thanks, I just ordered the official mercedes one, don't wanna mess with wrong electronics! thanks
 
#30 ·
Did you happen to check the voltage on your old battery? I removed my AUX battery tonight and it was ready 13v, but I'm still getting the AUX MALFUNCTION.

Just wondering if I should replace the battery even tho I'm getting 13v from it.

-Leo
 
#34 ·
I, too, have had the Auxiliary Battery Malfunction warning for a week. It has been a consistent warning each time the engine is started. The alert goes away when the "OK" button is depressed. Our 2016 Passenger Van has the "start/stop" feature. It has not worked since the warning started. When removed the battery, dated 03/16, measured 11.8 V. A fair amount of corrosion was present. A replacement has been ordered. I'll share the results in a week or so when it arrives.
 
#42 ·
It is location dependent and seasonal too. If you have enough cold weather the Eco start / stop does not even engage. :)

I stopped pressing the Dynamic button figuring I needed it for the best fuel economy.

I will turn off start stop, if I'm in a queue of cars like at the gas station, or there's a slow moving series of cars through a couple close by intersections, or the occasional drive through. The kind of thing where it may want to engage several times in a row; and it isn't a clean stop for a minute or so, then go.
 
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